When a module has a non-templated function that is pure and has auto result type, and at least one parameter, compiler segfaults when compiling another module that imports the first and invokes the function.

Test case:
---
module mod;

// parameter type doesn't matter,
// as long as there is at least one parameter
// and function is not templated
pure auto foo(bool b)
{
    return 1;
}

module main;
import mod;

void main()
{
    foo(true);
}
---
$ dmd -v test.d mod.d

binary    dmd
version   v2.051
config    /home/user/dmd.conf
parse     test
parse     mod
importall test
import    object	(/home/user/dmd2/src/druntime/import/object.di)
importall mod
semantic  test
semantic  mod
semantic2 test
semantic2 mod
semantic3 test
Segmentation fault

Removing pure or parameters or replacing auto with concrete type, or making function templated, resolves segfault. If the function is defined and used in the same module that is being compiled, segfault doesn't occur either.